Aircraft Heat Exchanger Finned Plate Manufacture

ABSTRACT

A method for forming a heat exchanger plate includes: securing a wave form metallic sheet to a heat exchanger plate substrate, the substrate comprising a first face and a second face opposite the first face, the securing of the wave form metallic sheet being to the first face; and removing peaks of the sheet.

CROSS-REFERENCE TO RELATED APPLICATION

Benefit is claimed of U.S. Pat. Application No. 62/963,068, filed Jan.19, 2020, and entitled “Aircraft Heat Exchanger Finned PlateManufacture”, the disclosure of which is incorporated by referenceherein in its entirety as if set forth at length.

BACKGROUND

The disclosure relates to gas turbine engine heat exchangers. Moreparticularly, the disclosure relates to air-to-air heat exchangers.

Examples of gas turbine engine heat exchangers are found in: U.S. Pat.Application Publication 20190170445A1 (the ‘445 publication), McCaffrey,Jun. 6, 2019, “HIGH TEMPERATURE PLATE FIN HEAT EXCHANGER”; U.S. Pat.Application Publication 20190170455A1 (the ‘455 publication), McCaffrey,Jun. 6, 2019, “HEAT EXCHANGER BELL MOUTH INLET”; and U.S. Pat.Application Publication 20190212074A1 (the ‘074 publication), Lockwoodet al., Jul. 11, 2019, “METHOD FOR MANUFACTURING A CURVED HEAT EXCHANGERUSING WEDGE SHAPED SEGMENTS”, the disclosures of which threepublications are incorporated by reference in their entireties herein asif set forth at length.

An exemplary positioning of such a heat exchanger provides for thetransfer of thermal energy from a flow (heat donor flow) diverted froman engine core flow to a bypass flow (heat recipient flow). For example,air is often diverted from the compressor for purposes such as cooling.However, the act of compression heats the air and reduces its coolingeffectiveness. Accordingly, the diverted air may be cooled in the heatexchanger to render it more suitable for cooling or other purposes. Oneparticular example draws the heat donor airflow from a diffuser casedownstream of the last compressor stage upstream of the combustor. Thisdonor flow transfers heat to a recipient flow which is a portion of thebypass flow. To this end, the heat exchanger may be positioned within afan duct or other bypass duct. The cooled donor flow is then returned tothe engine core (e.g., radially inward through struts) to pass radiallyinward of the gas path and then be passed rearward for turbine sectioncooling including the cooling of turbine blades and vanes. The heatexchanger may conform to the bypass duct. The bypass duct is generallyannular. Thus, the heat exchanger may occupy a sector of the annulus upto the full annulus.

Other heat exchangers may carry different fluids and be in differentlocations. For example, instead of rejecting heat to an air flow in abypass duct, other heat exchangers may absorb heat from a core flow(e.g., as in recuperator use). Among further uses for heat exchangers inaircraft are power and thermal management systems (PTMS) also known asintegrated power packages (IPP). One example is disclosed in U.S. Pat.Application publication 20100170262A1, Kaslusky et al., Jul. 8, 2010,“AIRCRAFT POWER AND THERMAL MANAGEMENT SYSTEM WITH ELECTRICCO-GENERATION”. Another example is disclosed in U.S. Pat. Applicationpublication 20160362999A1, Ho, Dec. 15, 2016, “EFFICIENT POWER ANDTHERMAL MANAGEMENT SYSTEM FOR HIGH PERFORMANCE AIRCRAFT”. Anotherexample is disclosed in U.S. Pat. Application publication 20160177828A1,Snyder et al., Jun. 23, 2016, “STAGED HEAT EXCHANGERS FOR MULTI-BYPASSSTREAM GAS TURBINE ENGINES”.

U.S. Pat. 10,100,740 (the ‘740 patent, the disclosure of which isincorporated by reference in its entirety herein as if set forth atlength), to Thomas, Oct. 16, 2018, “Curved plate/fin heater exchanger”,shows attachment of a square wave form fin array to the side of a heatexchanger plate body. For plates in a radial array, the wave amplitudeprogressively increases to accommodate a similar increase in inter-platespacing.

SUMMARY

One aspect of the disclosure involves a method for forming a heatexchanger plate. The method comprises: securing a wave form metallicsheet to a heat exchanger plate substrate, the substrate comprising afirst face and a second face opposite the first face, the securing ofthe wave form metallic sheet being to the first face; and removing peaksof the sheet.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include securing a second wave formmetallic sheet to the second face and removing peaks of the secondsheet.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the removing comprisingelectro-discharge machining.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the removing comprising wireelectro-discharge machining.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the removing comprising wireelectro-discharge machining with a wire removing the peaks in a singletraversal.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the removing removingprogressively more from one peak of the wave to the next across amajority of a footprint of the sheet.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the wave form being a squarewave form.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the securing comprisingbrazing.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the substrate comprising acasting.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the substrate comprising afirst edge having at least one port and the waves of the wave form arewithin 10° of parallel to the first edge.

Another aspect of the disclosure involves a method for forming a heatexchanger plate. A precursor is provided having a body with a first faceand a second face opposite the first face and a plurality of first finprecursors protruding from the first face and second fin precursorsprotruding from the second face. Material is removed from the first finprecursors and the second fin precursors via wire electro-dischargemachining.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include: (1) the precursor comprisingsaid body integrally cast with said first and second fin precursors; or(2) the precursor comprising: a plurality of said first fin precursorsas legs of a first wave-form sheet metal piece and one or more others ofsaid first fin precursors as portions of said body as a casting; and aplurality of said second fin precursors as legs of a second wave-formsheet metal piece and one or more others of said second fin precursorsas portions of said body as a casting.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include a method for forming a heatexchanger. The method comprising: forming, to the method above, aplurality of heat exchanger plates; and securing the plurality of heatexchanger plates to at least one manifold with a progressively varyingorientation.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the at least one manifoldbeing arcuate and the arcuateness provides the progressively varyingorientation.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include each said substratecomprising: at least one port mated to the manifold; and at least oneinternal passageway.

Another aspect of the disclosure involves a heat exchanger plate forproviding heat transfer between a first flow along a first flowpath anda second flow along a second flowpath. The heat exchanger platecomprises a substrate having: a first face and a second face oppositethe first face; a leading edge along the second flowpath and a trailingedge along the second flowpath; a proximal edge having at least oneinlet port along the first flowpath and at least one outlet port alongthe first flowpath; and at least one passageway along the first flowpathbetween the at least one inlet port of the plate and the at least oneoutlet port of the plate. The heat exchanger plate further comprises aplurality of fin structures along the first face, each fin structurecomprising: a base secured to the first face; and a first fin and asecond fin extending from respective first and second edges of the baseto respective first and second free edges.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the fin structures beingarrayed in parallel and progressively change in height from the firstface from one fin structure to the next.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the heat exchanger platefurther comprising a plurality of second fin structures along the secondface, each second fin structure comprising: a base secured to the secondface; and a first fin and a second fin extending from respective firstand second edges of the second fin structure base to respective firstand second free edges.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include a heat exchanger for providingheat transfer between a first flow along a first flowpath and a secondflow along a second flowpath. The heat exchanger comprising: at leastone plate bank comprising a plurality of plates described above. Foreach plate, the fin structures are arrayed in parallel and progressivelychange in height from the first face from one fin structure to the next.Within each plate bank, the progressive change in fin heightaccommodates a progressive change in plate orientation from one plate tothe next.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include: an inlet manifold having atleast one inlet port and at least one outlet port; and an outletmanifold having at least one outlet port and at least one inlet port,the first flowpath passing from the at least one inlet port of the inletmanifold, through the at least one passageway of each of the pluralityof plates, and through the at least one outlet port of the outletmanifold.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include the inlet manifold and outletmanifold being arcuate having a convex first face and a concave secondface. The at least one plate bank is mounted to the convex first faces.

A further embodiment of any of the foregoing embodiments mayadditionally and/or alternatively include a gas turbine engine includingthe heat exchanger. The first flow is a bleed flow and the second flowis a bypass flow.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a heat exchanger.

FIG. 2 is a view of a manifold unit of the heat exchanger of FIG. 1 .

FIG. 3 is a front end view of the heat exchanger of FIG. 1 .

FIG. 4 is an axial/radial sectional view of the heat exchanger of FIG. 1taken long line 4-4 of FIG. 3 .

FIG. 5 is a side view of a plate of the heat exchanger.

FIG. 6 is a transverse sectional view of the plate of FIG. 5 taken alongline 6-6 with exaggerated fin height.

FIG. 7 is a transverse sectional view of a precursor of the plate ofFIG. 6 .

FIG. 7A is an enlarged view of the plate precursor of FIG. 7 .

FIG. 8 is a partial view of multiple plates of FIG. 6 in acircumferential array in the heat exchanger.

FIG. 9 is a view of the plate precursor during electro-dischargemachining (EDM) of a fin array.

FIG. 10 is a view of an alternate plate precursor duringelectro-discharge machining (EDM) of a fin array.

FIG. 11 is a view of a second alternate plate precursor duringelectro-discharge machining (EDM) of a fin array.

FIG. 12 is a schematic axial half section view of a gas turbine engineincluding the heat exchanger of FIG. 1 .

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 shows a gas turbine engine heat exchanger 20 providing heatexchange between a first flowpath 900 and a second flowpath 902 and thusbetween their respective first and second fluid flows 910 and 912. Inthe exemplary embodiment, the flowpaths 900, 902 are gas flowpathspassing respective gas flows 910, 912. In the illustrated example, thefirst flow 910 enters and exits the heat exchanger 20 as a single pipedflow and exits as a single piped flow 910; whereas the flow 912 issector portion of an axial annular flow surrounding a centrallongitudinal axis (centerline) 10 of the heat exchanger and associatedengine. For purposes of schematic illustration, the exemplary heatexchanger 20 is shown shaped to occupy approximately 20° of a 360°annulus. There may be multiple such heat exchangers occupying the fullannulus or one or more such heat exchangers occupying only a portion ofthe annulus.

Other connections are also possible. For example, a configuration with asingle first flow inlet and branched first flow outlets is shown incopending U.S. Pat. Application No. 62957091 (the ‘091 application),filed Jan. 3, 2020, and entitled “Aircraft Heat Exchanger Assembly”, thedisclosure of which is incorporated by reference herein in its entiretyas if set forth at length.

The heat exchanger 20 has an inlet 22 and outlet 24 for the first flow.The exemplary inlet and outlet are, respectively, ports of an inletmanifold 26 (FIG. 2 ) and an outlet manifold 28 (discussed below) shownformed as portions of a combined manifold structure/unit 29. Themanifold 29 has a first face 100 (outer diameter (OD) in the example),an opposite second face 102 (inner diameter (ID) in the example), aleading end 104, a trailing end 106, and lateral (circumferential(circumferentially facing) in the example) ends/edges 108, 110. In theparticular arcuate manifold example, the OD face is convex and the IDface concave. Thus the respective manifold OD and ID surfaces/faces areportions of the faces 100 and 102

Exemplary manifolds are metallic (e.g., nickel-based superalloy). Theinlet manifold and outlet manifold may each have a respective fitting30, 32 providing the associated port 22, 24. As is discussed furtherbelow, the inlet manifold and outlet manifold are coupled to heatexchanger plates (panels) of one or more exemplary plate banks 40 (FIG.3 ). FIG. 2 also shows exemplary inlet manifold outlet ports 34 andoutlet manifold inlet ports 36 for such coupling.

Each plate bank 40 comprises a circumferential array 42 (FIG. 3 ) ofplates 44 (discussed further below). In the exemplary banks, the platesextend axially and radially relative to the axis 10. Thus, the platesdiverge from each other in the outward radial direction. Each plate hasan inlet port 46 (FIG. 4 ) mated to an associated inlet manifold outletport 34 and an outlet port 48 mated to an associated outlet manifoldinlet port 36 (e.g., plugs of the plate mated to sockets in an outerdiameter wall of the respective manifold). Each plate has internalpassageways 49 (example in FIG. 4 based on that of the ‘091 application)between the ports 46 and 48.

The schematic illustrations of the heat exchanger have environmental andother details such as shrouds, mounting hardware, deflectors/blockers,and structural brace hardware (if any) removed for purposes ofillustration.

Each plate 44 (FIG. 5 ) comprises a body or substrate 52 (e.g., cast oradditively manufactured alloy such as nickel-based superalloy) having aleading edge 54, a trailing edge 56, an inboard or inner diameter (ID)edge 58, an outboard or outer diameter (OD) edge 60, a firstcircumferential (generally circumferentially facing) face 62 (FIG. 3 )and a second circumferential face 64.

As is discussed below, one or both faces 62, 64 may bear fin arrays 70(FIG. 6 - shown for purposes of illustration with exaggeratedprogressive change in fin height relative to FIG. 3 ). The fins areseparately formed (e.g., of folded sheetmetal - e.g., nickel-basedsuperalloy) and secured (e.g., brazing, welding, diffusion bonding, andthe like) to adjacent substrate(s) (generally see the ‘740 patent). Asis discussed further below, exemplary fins are initially formed assquare wave corrugations 72 (FIG. 7 ) of even height/amplitude whosetroughs 73 (FIG. 7A) are secured to the associated face 62, 64. Thecorrugation has legs 74, 75 and peaks 76 and extends from a firstsectional end 77 (an inner diameter (ID) end in the example) to a secondsection end 78 (an outer diameter (OD) end in the example). Along thedirection of the individual corrugations (streamwise of the ultimatesecond flow 912) the corrugation has a first end near the platesubstrate upstream edge and a second end near the plate substratedownstream edge. In general, the term “plate” or “panel” may be appliedat any of several levels of detail. It may identify a body or substrateof an assembly or the greater assembly or subassembly (e.g., a castsubstrate plus one or more separately-attached fin arrays).

After the wave corrugation(s) are secured, the peaks 76 and portions ofthe legs 74, 75 are cut off to create discrete pairs of fins 80, 82(FIG. 6 ). Each fin extends to a free distal end/edge 84 and each pairare joined by the intact trough 73. At the ends (ID and OD in theexample) of the fin arrays, there may be boundary conditions whereby asingle isolated fin exists secured by an isolated trough remnant.

The exemplary trimming or cutting provides a progressive change in finheight from the associated substrate surface 62, 64. This allows aprogressive proximal-to-distal change in spacing between adjacentplates. For example, FIG. 8 shows two adjacent plates extending exactlyradially and diverging from each other by an angle θ. Exemplary θ is0.5°-10.0°, more particularly, 0.5°-3.0°. The fins are thus trimmed atan angle θ/2 so that spacing between fin tips of adjacent plates isuniform. Thus, in the illustrated example, from the ID end of the finarray to the OD end, the fins progressively increase in height. Such findivergence may be particularly advantageous for plates extending from anOD surface of an ID manifold; whereas a proximal-to-distal convergencewould be advantageous for plates mounted to the ID surface of an ODmanifold. Nevertheless, non-uniform spacing may be useful such as toallow greater clearance where there may be plate movement ordifferential thermal expansion.

FIG. 9 shows a wire electro-discharge machining (EDM) system 700 forremoving all peaks of a given wave corrugation 72 in a single traversal.The system 700 includes an EDM power supply 702 having leads 704A, 704Brespectively electrically connected to an EDM wire 706 (e.g., directlyor to a spool) and the plate precursor (e.g., by a clip or otherelectrical contact 710 engaging the fin precursor or the substrate). Theexemplary wire is held at the angle θ/2 and traversed parallel to thecorrugations (e.g., axially relative to the ultimate position of theexemplary plate in the exemplary heat exchanger). Other conventional EDMcomponents such as the wire holder, spools, and manipulator and theconductive fluid in which all may be immersed are not shown.

Relative to the ‘740 patent, the progressive height increasepost-cutting may have one of more of several advantages. In heatexchangers with progressive change in plate orientation (e.g., radialplates), the uniform amplitude of source stock may be less expensivethan forming source stock of progressive amplitude change. Assembly mayalso be eased because a relatively precise registry may be required forthe progressive amplitude wave to contact both adjacent plates. Byhaving separate fins on each adjacent plate face, slight variations ingaps between facing fins of the two plates or other artifacts ofinconsistency in fin position are of trivial consequence.

Although the illustrated example involves removing peaks from the entirespan S (FIG. 7 ), smaller fractions are possible (e.g., along a radiallyinboard portion of the corrugation 72, leaving radially outboard peaks76 intact. Thus an exemplary range is 50% to 100% of the span S or 75%to 100%.

FIG. 10 schematically shows an alternative plate 200 initially formed asa unitary piece (e.g., via casting) including a main body 202 andintegral fins 204 extending from opposite faces of the main body.General details of the main body may be similar to those of thesubstrates 52 of the plates 44. The fins 204 initially extend to distalends/tips 206. In an example of an initial plate precursor, this mayeffectively involve a uniform fin height. However, as with the plate 44,the fins on one or both sides may be cut to provide a progressive changein height along at least a portion of the area/footprint covered by thefins. FIG. 8 specifically shows fins on one side cut down leaving finalcut fin tips 208 while the fins on the other side are in the process ofbeing cut.

Additionally, combinations of cast fins and foil fins are possible andmay be simultaneously cut. FIG. 11 show a plate 250 with one or moreintegrally cast fins 204 along each side of a proximal portion 252 of abody and foil-formed fins 70 along each side of a distal portion 254.Fins on the drawing left side are cut away for illustration and fins onthe right side are in the process of being cut by wire EDM.

Although a reverse taper of final fin height is shown (height divergingfrom proximal to distal), other height profiles are possible includingconverging.

FIG. 12 schematically shows a gas turbine engine 800 as a turbofanengine having a centerline or central longitudinal axis 10 and extendingfrom an upstream end at an inlet 802 to a downstream end at an outlet804. The exemplary engine schematically includes a core flowpath 950passing a core flow 952 and a bypass flowpath 954 passing a bypass flow956. The core flow and bypass flow are initially formed by respectiveportions of a combined inlet airflow 958 divided at a splitter 870.

A core case or other structure 820 divides the core flowpath from thebypass flowpath. The bypass flowpath is, in turn, surrounded by an outercase 822 which, depending upon implementation, may be a fan case. Fromupstream to downstream, the engine includes a fan section 830 having oneor more fan blade stages, a compressor 832 having one or more sectionseach having one or more blade stages, a combustor 834 (e.g., annular,can-type, or reverse flow), and a turbine 836 again having one or moresections each having one or more blade stages. For example, manyso-called two-spool engines have two compressor sections and two turbinesections with each turbine section driving a respective associatedcompressor section and a lower pressure downstream turbine section alsodriving the fan (optionally via a gear reduction). Yet otherarrangements are possible.

FIG. 12 shows the heat exchanger 20 positioned in the bypass flowpath sothat a portion of the bypass flowpath 954 becomes the second flowpath902 and a portion of the bypass flow 956 becomes the second airflow 912.

The exemplary first airflow 910 is drawn as a compressed bleed flow froma diffuser case 850 between the compressor 832 and combustor 834 andreturned radially inwardly back through the core flowpath 950 via struts860. Thus, the flowpath 900 is a bleed flowpath branching from the coreflowpath.

The use of “first”, “second”, and the like in the following claims isfor differentiation within the claim only and does not necessarilyindicate relative or absolute importance or temporal order. Similarly,the identification in a claim of one element as “first” (or the like)does not preclude such “first” element from identifying an element thatis referred to as “second” (or the like) in another claim or in thedescription.

One or more embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made. For example, whenapplied to an existing baseline configuration, details of such baselinemay influence details of particular implementations. Accordingly, otherembodiments are within the scope of the following claims.

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 10. (canceled) 11.A method for forming a heat exchanger plate, the method comprising:providing a precursor having a body with a first face and a second faceopposite the first face and a plurality of first fin precursorsprotruding from the first face and second fin precursors protruding fromthe second face; and removing material from the first fin precursors andthe second fin precursors via wire electro-discharge machining.
 12. Themethod of claim 11 wherein: the precursor comprises said body integrallycast with said first and second fin precursors; or the precursorcomprises: a plurality of said first fin precursors as legs of a firstwave-form sheet metal piece and one or more others of said first finprecursors as portions of said body as a casting; and a plurality ofsaid second fin precursors as legs of a second wave-form sheet metalpiece and one or more others of said second fin precursors as portionsof said body as a casting.
 13. A method for forming a heat exchanger,the method comprising: forming, according to the method of claim 11, aplurality of heat exchanger plates; and securing the plurality of heatexchanger plates to at least one manifold with a progressively varyingorientation.
 14. The method of claim 13 wherein: the at least onemanifold is arcuate; and the arcuateness provides the progressivelyvarying orientation.
 15. The method of claim 13 wherein each saidsubstrate comprises: at least one port mated to the manifold; and atleast one internal passageway.
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 22. (canceled)23. The method of claim 11 wherein: the precursor comprises said bodyintegrally cast with said first and second fin precursors.
 24. Themethod of claim 11 wherein: the precursor comprises: a plurality of saidfirst fin precursors as legs of a first wave-form sheet metal piece andone or more others of said first fin precursors as portions of said bodyas a casting; and a plurality of said second fin precursors as legs of asecond wave-form sheet metal piece and one or more others of said secondfin precursors as portions of said body as a casting.
 25. The method ofclaim 24 wherein: the first wave-form sheet metal piece, the secondwave-form sheet metal piece, and the casting are of nickel-basedsuperalloy.
 26. The method of claim 11 wherein: the removing compriseswire electro-discharge machining with a wire removing the material fromthe first fin precursors in a single traversal and a wire removing thematerial from the second fin precursors in a single traversal.
 27. Themethod of claim 11 wherein: the providing comprises casting ofnickel-based superalloy.
 28. The method of claim 11 wherein: theproviding comprises additively manufacturing of nickel-based superalloy.29. The method of claim 11 wherein: the wire electro-discharge machiningcomprises traversing the wire parallel to the first precursors to cutthe first precursors and traversing the wire parallel to the secondprecursors to cut the second precursors.